Japanese Patent No. 4985639 discloses, as an example of a liquid ejection device, an inkjet printer. The inkjet printer comprises an inkjet head (liquid ejection head) for ejecting an ink, and a buffer tank (liquid supply tank) disposed above the inkjet head and supplying the ink to the inkjet head.
The inkjet head includes four ink inlet ports to which inks of four colors (of black, magenta, yellow and cyan) are supplied. Here, one ink inlet port is provided for each of the black ink and the magenta ink while two ink inlet ports are provided for each of the yellow ink and the cyan ink. In other words, the inkjet head includes six ink inlet ports in total. The six ink inlet ports are arranged along a scanning direction of the inkjet head.
The buffer tank is connected to four ink tanks through tubes, and the inks of the four colors are respectively supplied from the four ink tanks to the buffer tank. The buffer tank includes six liquid chambers respectively corresponding to the six ink inlet ports of the inkjet head. Here, two liquid chambers are provided for each of the yellow ink and the cyan ink similarly to the ink inlet ports, and the two liquid chambers to which the ink of the same color is introduced are communicated with each other. Besides, the six liquid chambers are arranged along the scanning direction of the inkjet head correspondingly to the six ink inlet ports. The ink supplied from the ink tank to the buffer tank flows into the liquid chamber. Here, if air is mixed with the supplied ink, while the ink is flowing from the liquid chamber to the ink inlet port of the inkjet head disposed below, the air mixed with the ink is separated from the ink to stay in an upper portion of the liquid chamber. Accordingly, the ink contained in the buffer tank is supplied to the inkjet head after the air is separated and removed in the liquid chamber.